In a patient with respiratory acidosis, how do the kidneys respond in terms of HCO3- excretion?

In the case of respiratory acidosis, the primary issue is an accumulation of carbon dioxide (CO2) due to inadequate ventilation, leading to an increase in hydrogen ion concentration (H+) in the blood. The kidneys play a critical role in maintaining acid-base balance and respond to changes in blood pH.

During respiratory acidosis, the kidneys will typically decrease the excretion of bicarbonate (HCO3-). This is because bicarbonate acts as a buffer to help neutralize the excess hydrogen ions in the bloodstream. By retaining bicarbonate, the kidneys help to raise the blood pH back towards normal levels. This compensatory mechanism effectively works to mitigate the acidotic state by increasing the availability of bicarbonate to neutralize acid.

It is important to understand that in a state of acidosis, whether metabolic or respiratory, the kidneys work to conserve bicarbonate to provide a counterbalance to the increased acidity. Thus, the overall response to respiratory acidosis involves diminishing HCO3- excretion as the kidneys seek to correct the acid-base disturbance.